My thundercat - Page 24

GuyC · 17 May 2021, 12:50

I spent 10 minutes looking at this during lunch and whilst that 10 minutes reading is the sum total of my knowledge on the topic, I'd say that the fuel has water in it and it has caused the ethanol to separate from the fuel.

https://www.bellperformance.com/blog...tion-water-e10

Roflhat · 17 May 2021, 13:05

Interesting read, sounds like my issue. Guess it wouldn't take much water to cause the ethanol to seperate. I appreciate the 10 minutes you spent! Going to get a water seperater filter from Yamaha too

ThundercatRob · 17 May 2021, 22:04

Which water separators do you guys normally use?

I’ve currently got a Quicksilver in-line cartridge type bolted onto the transom. It’s not looking the best as the housing is a bit corroded. I was thinking of just replacing with the same so the holes line up in the transom.

My Thundercat never had one, so I’ve no experience of these!

GuyC · 17 May 2021, 22:12

In the interests of saving weight, could you polish the fuel before you put it into your boat tank?

Pikey Dave · 17 May 2021, 22:59

Quote:

Originally Posted by ThundercatRob

Which water separators do you guys normally use?

I’ve currently got a Quicksilver in-line cartridge type bolted onto the transom. It’s not looking the best as the housing is a bit corroded. I was thinking of just replacing with the same so the holes line up in the transom.

My Thundercat never had one, so I’ve no experience of these!

Have a look at the Racor Snapp. All non-corrosive & sealed.

Roflhat · 18 May 2021, 16:24

I think the current issue must be water getting into the fuel once it's in the boats tank, going to take it apart and re seal the top.

The yamaha water seperaters are good, I'm going to get one of the smaller ones and run it under the cowling

Roflhat · 13 July 2021, 18:28

Seem to have sorted the water in the fuel tank, removed some worn rubber seals from the tank and made a U shaped breather to stop water going in. Also had an issue with the engine dropping onto 2 cylinders, turned out to be a loose bolt on one of the pickup coils under the flywheel. Engine now going better than ever, jets are 170/180/180, not running the additive any more as the supply has dry. Using octane booster with Toluene instead, plugs are the perfect colour so happy with that.

Booked accomodation for Coniston again this year, hopefully goes ahead! Need to find a copilot whos 50kg or less, any volunteers?

Steve509926 · 13 July 2021, 21:31

Quote:

Originally Posted by Roflhat

Booked accomodation for Coniston again this year, hopefully goes ahead! Need to find a copilot whos 50kg or less, any volunteers?

96kg - but Diane, my better half, assures me that Sliming World really works! So you can put me down for it.

Roflhat · 14 July 2021, 17:12

Quote:

Originally Posted by Steve509926

96kg - but Diane, my better half, assures me that Sliming World really works! So you can put me down for it.

Ideal, just need to half your body weight!

Zapcatf1 · 22 July 2021, 19:04

Hi, I just bought a new zapcat f1 and looking for all the help to get engine set up right first time round.. any advice on height and things to do..
Haven’t got an engine yet so best engine for fast leisure use.. tohatsu 50hp I’m finding hard to find.. will anything more modern and bigger work? Speed is important to me!!
Any important things to know when building from scratch... novice to these boats but want to build a very capable boat..
many thanks

ThundercatRob · 22 July 2021, 21:31

Roflhat is certainly the man when it comes to fast Zapcat / Thundercat.

I previously owned a Ceasar Thundercat and they are a great platform for messing about in!

Is yours a brand new hull?

You could also maybe look for a Yahama or Mariner engine if you’re struggling with a Tohatsu.

I’ve currently got a Gemini GRX 420 (like a zapcat with a rounded bow) that Roflhat and others are trying to help me get up to speed. It’s a bit slow at the moment, and I need to make a few tweaks to the engine setup. You may find some of the info useful in setting up your boat:
https://www.rib.net/forum/f50/anyone...0-a-85723.html

Zapcatf1 · 23 July 2021, 12:27

Thanks for your response, yes roflhat looks like they now what they’re talking about..
yes my hull is brand new, straight out the box so full set up is needed. If you know of any good newer engines around, let me know..

Roflhat · 24 July 2021, 07:11

Any photos of your boat? Interesting chines on the new Geminis although I'm yet to try one

A good starting point regardless of engine is to have the centre of the propshaft 10mm above the bottom of the hijackers. I run string across the bottom of the boat to get a reference. Tube pressures 6psi top tubes and 12 in the hijackers.

Tohatsu and Yamaha 40/50hp are the go to engines for these boats and will give you a very well balanced and fast setup. Some guys are putting the new Mercury 60hp 4 strokes on them, much heavier at 112kg vs around 85kg but they are quick. No pull start so you'd need a battery too and would be very difficult to restart should you flip it.
Fast cats in Australia make a conversion kit for the 70hp tohatsu 2 stroke which mounts it onto the 50hp leg. Not cheap but seriously cool!

Or the Yamaha 70ces is an ideal engine with some tweaking but they're getting rare nowadays.
You can also make a Yamaha 90hp short shaft using only factory parts, would be a lot of fun. All depends how far you want to go, but 50hp with correct setup is usually fast enough for most folk. You can make some basic mods for more performance too, prop selection is where the performance is

Zapcatf1 · 24 July 2021, 13:05

Thanks roflhat for all the info, very helpful. Will I have to strengthen the transom at all putting a heavier engine on or can the zapcat take the extra weight? Love the Mercury 60 setup I’ve seen. If you know of any engines about I will be very interested.
Struggling to upload a photo, was expecting double chimes when I blew it up but only a single.. Spoke to the factory and they said the doubles were prototypes and only built 6. Acceleration was slower apparently..

Roflhat · 03 August 2021, 11:29

Sorry I’ve just seen this, most of the new hulls now are rated for 70hp so you should be alright. Not sure I’d fancy jumping waves with the new mercury 60 though. All the 2 strokes are lighter than it, I imagine even a short 90 would be

For photos I use this site - https://imgbb.com/
Then copy and late the bbcode full linked address

Roflhat · 20 September 2021, 20:38

Couple shots from the summer

and video https://streamable.com/ypxiue

Steve509926 · 20 September 2021, 21:37

That looks one stealthy bit of kit against the emerald green water.

Roflhat · 02 October 2021, 11:17

New stickers on for Coniston

Roflhat · 07 October 2021, 19:25

More testing done yesterday, early morning had a couple hours calm. Consistent 76mph + each run, tried the new cylinder head I designed which gave a bit more power. Well chuffed with that! 76.7mph top speed, couldn't get my biggest prop to settle so need to try a couple setup tweaks.
New car too, Subaru Legacy 3.0 Spec B Auto

T shirts designed for Coniston

spartacus · 07 October 2021, 20:22

Cracking picture.

Is that your first Subaru?